Pitched roofs are a type of roof that slopes at an angle exceeding 10° from the horizontal. These roofs play a crucial role in areas prone to extreme weather conditions like wind, rain, and snowfall. Let’s delve into the characteristics, materials, and various types of pitched roofs.
Pitched roofs come with specific features that make them suitable for diverse applications. Here are some key characteristics:
1. Slope Angle Consideration : The slope angle of a pitched roof is vital, and it increases in proportion to factors like wind, rain, and snow. However, it’s important to note that the slope should not exceed 60°.
2. Material Composition : Pitched roofs can be constructed from various materials, including timber, structural steel, RCC (Reinforced Cement Concrete), and prestressed concrete. This versatility makes pitched roofs suitable for diverse applications.
3. Geographic Applicability : Pitched roofs are especially prevalent in hilly areas and regions exposed to harsh weather conditions, such as strong winds, heavy rains, and snowfalls. Additionally, they are commonly used for large-span structures like factory buildings, warehouses, and workshops.
Diverse architectural needs have given rise to different types of pitched roofs. Let’s explore some of the common ones:
1. Lean To Roof : The simplest form of pitched roof with a slope on one side only. It finds use in applications such as verandahs and small sheds.
2. Coupled Roof : An advanced version of the lean-to roof with slopes on both sides of the ridge. Suitable for spans up to 3.6 m.
3. Couple-Close Roof : Similar to the coupled roof but with common rafters connected by a tie beam near the lower ends. Applicable for spans up to 5 m.
4. Collar Roof : The tie beam is fixed at a higher level, providing more height to the room. Maximum span: 5 m.
5. Scissors Roof : Consists of two common rafters and additional members (scissors members) to strengthen the roof.
6. Double or Purlin Roofs : Utilizes struts under the rafters for spans exceeding 5 m.
7. King Post Truss : Involves principal rafters, tie beam, struts, and a king post. Suitable for spans from 5 m to 9 m.
8. Queen Post Truss : Includes queen posts, principal rafters, struts, tie beam, straining beam, and purlins. Suitable for spans from 9 m to 14 m.
9. Mansard Truss : A combination of king post and queen post trusses.
10. Steel Truss : Among the strongest pitched roof types, made from rolled steel structural members. Economical for spans exceeding 10 m.
11. Truncated Truss : The lower part of the mansard truss.
12. Bel-fast Truss : Features a curved top surface, made from timber sections, suitable for spans up to 30 m.
13. Composite Truss : Made by combining timber and mild steel sections for enhanced structural integrity.
In conclusion, understanding the diverse types of pitched roofs and their characteristics allows for informed decisions in choosing the most suitable option for specific architectural needs.
